javascript's event handler in separate html file and javascript file

Question

I want to write javascript's event handler in separate html file and javascript file. I am in trouble because it does not work if it is the method of reference site. Sample Site : https://techacademy.jp/magazine/15062

How do I write event handlers in javascript without writing event handlers in html? I would like to write it in a way like a sample site.

Answer 1

write code in a separate js file and add on the HTML using <script> file just before </body>

<script type="file/path/name.js"></script>

is that you are asking about?